Computed Tomography (CT) is a major tool in diagnostic imaging. X-ray detection technology typically uses energy-integrating detectors that add electrical signals, from interactions between an X-ray beam and a material of the detector, over the whole spectrum. Energy-integrating detectors often lose spectral information. Spectral CT (SCT) has advantages over conventional CT by offering detailed spectral information for material decomposition. SCT can also reduce beam-hardening artifacts and radiation dose. However, related art SCT is slower, less stable, and much more expensive than conventional CT.